Brazil's sports minister says he is concerned about the pace of construction at the 2014 World Cup stadiums that need to be ready in December.

Aldo Rebelo said Tuesday that work needs to be accelerated at five of the six stadiums that are under construction because they ''are facing a tight deadline.'' The minister said that only the Sao Paulo stadium that will host the opening match next June is comfortably on track to be completed on time.

FIFA has made it clear that it wants all 12 stadiums ready by December. It has said it won't tolerate the kind of delays that afflicted the stadiums used in the Confederations Cup earlier this year.

Only two of the six Confederations Cup venues were completed by the end of 2012 as FIFA had originally wanted. Football's governing body made exceptions for this year's event but said it would not do the same ahead of football's showcase tournament.

FIFA secretary general Jerome Valcke reiterated recently that it's crucial to have all 12 World Cup stadiums ready this year and said organizers would increase monitoring of construction work at the venues. Valcke plans to visit Brazil next Monday to inspect work in Sao Paulo, Curitiba and Manaus.

''We can get everything done in time, but we will need to speed up the pace of the construction work,'' Rebelo said at a senate hearing on Tuesday.

Rebelo, the government official in charge of the country's preparations for the World Cup and the 2016 Rio Olympics, made a similar pledge last week, calling for the host cities to pick up the pace at the construction sites.

''Sao Paulo is in an advanced stage with more than 80 percent of the work done, but the others are facing a tight deadline,'' he said. ''We need to improve the pace in most of the stadiums if we want to deliver them by the (December) deadline.''

Four of the stadiums are less than 80 percent completed - in Curitiba, Manaus, Natal and Porto Alegre. The venue in Cuiaba is 80 percent ready, according to the sports ministry.

''It's possible to intensify the work now by adding more engineers and more workers,'' Rebelo said. ''We couldn't do that in the earlier stages, but now we can.''

The minister said it's important to get the stadiums ready this year so local organizers can host the necessary test events before the World Cup begins. FIFA usually wants at least three test events at each venue, but that didn't happen in most of the Confederations Cup stadiums because of the construction delays.